Thermostatic device



Dec. 2, 1930. E, 'A RUTEQBER 1,783,309

THERMOSTATI C DEVI CE Filed Sept. 19, 1928 2 Sheets-Sheet l Dec, 2,193(0). E. A. RUTENBER 1,783,309

THERMOSTATIC DEVICE Filed Sept. 19, 1928 .2 Sheets-Sheet 2 OJHHIIIIHlliln O Swumtez Patented Dec. 2, 1930 UNITED STATES PATENT orrlca EDWINA. RUTENBER, 01 IILWAUKEE, WISCONSI N, ASSIGNOR TO J. LINDEMANN HOV'EBSON COMPANY, OF MILWAUKEE, WISCONSIN, A. CORPORATION OF WISCONSINrnmosrarrc DEVICE Application filed September 19, 1928. Serial No.306,885..

The improvements relate to thermally operated devices for automaticallycontrolling the temperature of ovens, water heaters and the like, andare primarily adapted to be used in connection with apparatus of the tye aforementioned which are arranged to be electrically heated, but haveother applications. Their objects are, among others, the

was

provements adapted provision of a thermostatic control which may beadjusted and set so as to maintain various temperatures by acting on theheating medium and preventing it from raising the temperature above orpermitting it to fall below the predetermined point and to make themechanism whereby the control is effected, accurate and'dependable inits operation.

A further object is to improve the construction and arrangement ofparts, including the heat responsive member, switch and theirconnections, rendering same more eflicient, durable and strengthening aswell as simplifying the construction and assembly thereof; and to reducethe number of operative parts to a minimum, to dispose them in compactand intimate relation whereby the movement of the terminal wires issubstantially negligible.

The present improvements are further designed to conserve the energy ofthe heat responsive member and to minimize the load said member iscalled upon to withstand in operating the switch, and to generallypreserve the life of'service of all the parts.

The improvements are illustrated in the accompanying drawings, in whichFig. 1 is a side elevation, with side cover removed, of one embodimentof the present imfor use in electric heaters;

Fig. 2 is a view similar to Fig. 1, with parts omitted and the switchand holder therefor in dotted lines;

Fig. 3 is a sideview of a detail of construction, illustrating the suporting member, thermal element and switc actuatmg mechanism;

Fig. 4 is an end view taken on line 44 of Fig. 3; p r V ig. 5 is asideelevatioh of a modified form adapted. for-use in water heaters.

control of the present improvements is deto the medium to be heated.

In Figs. 1 and 2, the plate 5 represents the side wall of a stationaryhousing defined by laterally extending walls 6, 7 and 8, having screws 9for securing a cover plate (not shown). In the present illustration, theleft hand limit of the housing is completed by segmental cover plate 10fixed to the housing by screws 11, said plate 10 being adapted toprotrude through the oven or heater wall. The plate 10 is provided witha curved window 12- and has a chord slot 13 in its side through whichthe handle 14 of'the indicator projects and in which it moves. The scale15 ,is arcuate in form and fixed in position by screws 11 asillustrated. Said scale has numbersand graduations thereon to indicatetemperatures, is positioned for observation through window 12, and thepointer (not shown) on handle 14 is arranged to travel in closeproximity over said scale for accurately indicating temperatures.

The handle 14 and pointer are fixed to the end of arm 16, which in turnis fixed to a segmental gear 17 pivotally mounted on wall 5 at 18. Asillustrated the gear 17 is normally in mesh with the teeth of an annularcollar 19 as hereinafter more fully described.

Referring now to the arrangement illustrated in Figs. 3 and 4 whichextends, when assembled, at right angles and away from the structureshown in Figs. 1 and 2, the stationary wall 5 is suitably perforatedto-receive an inwardly extending cylindrical portion 20 suitably fixedto said wall to form a bearing. Housed in said bearing 20 is a rotatablesleeve 21 in the form of a supporting member which is axially bored toreceive and loosely support an actuating element 22. Said element in thepresent illustration, com-. prises a rod protruding a substantialdistance in each direction beyond the limits of supporting member 21.The right handends of said member and rod 22 are operatively con- I.nectedby a thermostatichelicalband '23, havly seen in Fig. 3, the lefthand portion of rod 22 is machined to a smooth finish where it extendsthrough member 21 and protrudes therefrom. This smooth surface serves asa bearing for a contactor holder 27 which is loosely supported thereoninpivotal relationship. An actuating arm 28 is keyed or otherwise fixedto rod22 between the position of said holder and the member 21, wherebysaid arm describes an arcuate course in response to rocking movements ofsaid rod. A screw 29 is provided at the end of rod 22 forremovablyretaining the contactor holder 27' on said rod and preventingsame from sliding ofi the rod longitudinally.

The annular collar or ring 19, previously referred to, is rotatablymounted on the projecting hub 30 of the sleeve or supporting member 21,'but is frictionally held to said member b a toothed disk or ring 31keyed to said hu A set screw 32 is provided on collar 19, whichfunctions to secure disk 31 and collar 19 infixed relation so that theymay move together. To adjust the collar 19 therefore, with respect tothe sleeve 21,-it

is only necessaryto loosen set screw 32, thus disconnecting thetwo andto move collar 19 the desired e'xthtgthen tighten the screw and securethe two parts in position. It is apparent that .the toothed disk 31serves as a member for engagement by a screw driver or the like toprevent move mentof hub 30 while collar 19 is being slipped relativethereto. In this simple manner the device may be calibrated when it isassembed and mounted in the oven or heater, or at any other time.

The contactor holder 27 is in the form of a cradle .or carriage, withapertures 33 to. re-

' ceive the machined end of rod 22 on which it is loosely supported. S

ced spring clips 34 and 35 are formed on t e holder for removl ablyholding switch or contactor 36. The contactor is thus held and.positioned laterally of the elements 22 and 23 soas to be spaced asubstantial distance therefrom. One of said clips extends upwardly toform a member 37 [having a laterallyextending shoe 38and a seental arni39,- the latter having spaced upstanding lugs T40 and 41 which cooperatebe made of materialsuitable msaeoe The switch mechanism employed com- Iprises the contactor 36 consisting of a vessel of non-conductivematerial such as glass,

having a. globule 44 of conductive material therein in its horizontalbottom. The electric terminals 45 and 46 extend into said vessel andhave enlarged contacts in spaced wells 47 and 48 of the vessel, so thatwhen the vessel 36 is horizontal and the fluent conductor 44 level inthe bottom thereof, it will be in contact with both terminals and willclose the circuit, thus energizing the heating coils.

Obviously, if the vessel iscanted slightly from the horizontal,the'globule will gravitate to one end of the vessel and break thecircuit. The globuleis preferably mercury, but may be made of any otherconductive material suitable for the purpose. Terminal wires 49 and 50connect the terminals of the switch to the heat generator, said wiresbeing suitably insulated, relatively short in extent but suficient topermit freedom of movement for the contactor 36. Due to the arrangementof the present improvements, the wires are practically never disturbedwhile the switch is functioning and therefore may be of minimum length,to facilitate housing of same without danger of having same crossed,en-' tangled or interfering with the proper operation of the device. IThe present improvements are illustrated in assembled relation inFig. 1. The position of the rotable supporting member 21 may be adjustedby operating handle 14 by WlllCll rotary movement is transmitted to saidmember and to actuating rod 22 and arm 28. It is notable that duringthis setting movement the 'contactor holder 27 and contactor 36 are notmoved but remain' in true horizontal position as seen in Fig. 1 byreason of the weight 43 holding these parts against stop member 42. 1111the illustrated position the device is setto operate at a very lowtemperature and due to the mass and friction of the parts the member21is maintained in its set position against rotatiom, Therefore when thethermostatic coil 23 has been expanded by the heat in the oven toasuficient extent to move the arm 28 into'eontact with shoe 38,

in a clockwise direction, and the temperature continues to rise, the rod22 ismovedand causes to rock the arm'2 8 andiurge the shoe v Y whichisin the path .of travelof said arm 28 with lug 42 on wall 7 to, limitthe rocking movement oi the holder and eontactor. The

center-of mavity'of theforegoing strueture 3 38 in a clockwise directionin opposition to the energy of weight 43, thus eanting the .terminalsthus breaking the circuit.

If now the temperature falls below the given point the arm 28 moving ina counter clockwise direction, will be withdrawn from the shoe 38 andthe holder 27 and contactor 36 permitted to move totheleft under theinfluence ofweight 43, so that the vessel 36 is canted in the oppositedirection and the globule moved to circuit closing position.

Attention is directed to the fact that the contactor is normally inoperative position with the circuit closed, namely, in horizontalposition, as illustrated in Fig. 1. In this position it is seen that theactuating arm 28 is but a slight distance from the shoe 38 and thereforeonly a short travel of the former is required to break the circuit. Theposition of the contactor when the circuit is broken is indicated indotted lines in Fig. 2.

To raise the temperature of the oven the handle 14 is raised to thedesired position which will rock supporting member 21 in a counterclockwise direction so as to withdraw actuating arm 28 further away fromshoe 38 so that the circuit will remain closed until the temperature hasrisen to a point sufliciently high to bring the arm 28 in contact withthe shoe 38 through the expanding of thecoil 23. If it is desiredto-lower the temperature the handle 14 is depressed thus causing the arm28 to approach shoe 38 and thus break the circuit, and this conditionwill continue until the temperature has fallen to a point sufiicient tocause a contraction of the thermostatic band 23 which will withdraw arm28 from shoe 38. r I

It is obvious from the foregoing that the thermostatic switch is mountedin a holder free to move on an axis without any operating leversconnected thereto. The energized means 43 always tends to pull thecontactor to the closed position, and the stop 42, limiting the movementof holder 27, is entirely free from any thermostatic portion of theconstruction. Accordingly when the temperature rises, the expansion ofband 23 and rocking of arm 28 is unimpeded and unburdened' for the majorportion of its travel, until a predetermined position is reached, whencethe arm 28 loosel pushes against shoe 38 of the holder 27, tilting sameuntil contact is broken. Aside from the feature of conserving the energyof the band 23 and thus preserving its life, the other distinctadvantages are attained by the'present improvements. Pri marily, it isnotable that the switch mechanism describes only a very small movement,as is obvious, and does not have to tilt the distance required were itfixedly secured to.

the thermostatic element '23; .Especiallyis this true when consideringthat temperatures from room temperature up to 600 Fahrenheit are coveredby the present improvements. Should the switch herein be required topartake in tilting movement necessitated by a temperature range of 500Fahrenheit, the movement would be prohibitive, because, among otherreasons, the terminal wires would have to be wound around, cross eachother and be otherwise entangled, whereas in the present arrangement,the very small movement of the switch permits the use of shorter wireswhich are practically never disturbed.

A further feature of importance resides in loosely mounting the switchmechanism on the actuating rod 22. This refinement of construction notonly promotes compactness,

but also contributes to the conservation of energy of the coil 23 androd 22, by location of the contactor closely adjacent the power arm 28and shoe 38. Assembly of the parts is also greatly facilitated due tothe few number of parts. It isnotable that the structure illustrated inFig. 3 is bodily removable as a whole whence it may be readilydismembered or reassembled.

The modified form illustrated in Fig. 5 is adapted for use in waterheaters, and although not shown, is provided with an imperforateprotective covering over band 23 in place of cage 26. The generalorganization is substantially the same as that previously describedexcept that the collar 19 has no toothed portion but is equipped with anintegral arm 55, having an arcuate slot 56 and pointer 27. Furthermorethe fixed bearing (seen in Fig. 3 but not in Fig. 5) has a fixed support58 on the inside of the housing 59, said "support carrying terminalposts 60, stop lug 61 and a scale plate 62. As illustrated, the arm issuperposed in intimate relation with plate 62, whereby the thermal.element and actuating mechanism may be set at the desired temperature byappropri ate operation of set screw 63, which holds arm55 to plate 62and against unintentional rotation. Calibration of this modifiedstrucwith electrically heated ovens and the like,

but may, withother small modifications, be:

adapted for use in connection with other heating media. Various changesin the construction and arrangement of the parts may also be madewithout departing from the invention.

1 claim: l. A thermostatic control for electrical apparatus comprising asupportingmember, a

movable actuating element supported by said member, thermally responsivemeans operatively connected with said member and element, meansfrictionallyv secured to said member for adjusting the position thereof,an arm fixed to said element, a contactor ops erable by said arm, saidactuating element constructed and arranged to loosely support saidcontactor and manually operable control means for varying the posltionof both said member and said element 1 x 2. A thermostatic control forelectrical apparatus comprising a rotatable support normally fixedagainst rotation, an actuating rod extending loosely through saidsupport, a thermal element havin one end secured to said support and itsot er end fixed to said rod, an actuating arm fixed to said rod, a con-otactor loosely mounted on said rod and poslt ioned for movement in onedirection by said arm, said contactor having means for 2g constantlyurging same in a direction opposite to said first named direction, andmeans limiting the movements of said contactor.

3. In a thermal control device, the combination of an axially boredsupporting mem-' her, a rod loosely housed in the bore of said memberand protruding from each end thereof, a thermal coil connecting adjacentends of said member and rod, an arm fixed to said rod adjacent theopposite protruding end thereof whereby movements of said coil inresponse to thermal variations actuate said arm, a holder looselymounted on said rod adjacent said arm, said holder having meanspositioned in the path of travel in one direction of said arm, acontactor mounted on said holder, and energized means opposing theaforementioned travel of said arm,

4. In a thermal control device, the combination of an am'ally boredsupporting member, a rod loosely housed in the bore of said member andprotruding from each end thereof, a thermal coil connecting adjacentends of said member and rod, an' arm fixed to said rod adjacent theopposite protruding end thereof whereby movement of said coil inresponse to theme variations actuate said arm, a holder loosely mountedon said rod adjacent said arm, said holder having means positioned inthe path of travel in one direction of said arm, a contactor mounted onsaid holder, energized means on said holder opposing the aforementionedtravel of said arm and leans for limiting the=movement oi said holder.

5. Athermostatic control for'electrical apparatus comprising asupporting member, a movable actuating element supported by said member,thermally responsive means operatively connected with said member andele- 6 ment, adjustable means for varying the po- 7 sition of saidsupporting member, a contactorloosely mounts on said actuatin elentenergized means for normally ho dingsai-d contactor in circuit closingposit1on in ti 0- 6 sitions oi adjustment of id supporti ng portion toanother of said bottom.

meaeoe 6. In a device o fthecharacter described, a I

switch mechanism comprising a holder having means for pivoting same, aweight mounted on said holder on one side of said pivoting means, alaterally extending lug adapted to be contacted, by a moving element,upstanding spaced lugs adapted to limit the arcuate travel of saidholder, spring clips on said holder and a mercury tube removablydisposed in said clips.

7. A thermostatic control for electrical a paratus comprising asupporting member,'a movable actuating element supported by said member,a vessel having fluent conductive material therein, electric terminalsextending into said vessel and into the path of said fluent material,said vessel being loosely mounted on said actuatin element whereby saidvessel maybe cante to cause.

the said fluent material to move to and from the electric terminals,automatic means for normally maintaining said vessel in a'given positionand causing it to return to said position after being moved therefromcomprising an energized element associated with said last named meansand thermostatically controled and adjustable means for movingsaidvessel from such position, said last named means 0 eratively connectingsaid support-' ing mem er and said actuating element, said fluentconductive material being in the form of a globule andsaid vessel havinga bottom in appmximately horizontal position, but arranged to assumepositions slightly angular thereto when the vessel is canted and tocause the said conductive material to flow from one 8. A thermostaticcontrol for electrical apparatus comprising a supporting member, a.movableactuating element supported by said member,thermallyr'esponsivemeans o eratively connected with said member- 'an"=-element, anormally closed contactor fulcrumed on said actuatingelement,'means for trans-.

mitting movement induced by temperature rise from said element tosaidcontactor whereby the latter is rendered inoperative and meansindependent of temperature variations for restoring'said contactor toopera-" tive position I I 9. A thermostatic control for electricalapparatus comprising a supporting member,

a movable actuating element suppor ed by. :saidmember, thermal meansoperatively connecting said member and element, an actuating armoperatively associated with said element, a contactor fulcrumed on saidelement, movable relative thereto and pcsi-.

tioned for movement in one direction by said arm, and weighted meansassociated with said contactor for moving same in an opposite direction.

Witness my hand this 10 day of September, 1928., County of Milwaukee,State of Wiscousin,

EDWIN A. RUTENBER.

